Year	% (national estimate)
1966	68.22
1975	73.13
1980	70.08
1984	66.52
1989	57.01
1997	50.04
2005	42.833
2006	41.082
2007	41.187
2008	40.727
2009	39.55
2010	41.811
2011	42.74
2012	47.06
2013	44.518
2014	39.417
2015	39.409
2016	41.243
2017	41.316
2019	46.775
2022	32.528
2023	31.357